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SJY Zeph Open-Back Headphones Review: Music Through Magnets
How much of a difference can the earpads on a set of headphones really make? The idea of getting a noticeable sonic difference based on the size and shape of thin pieces of foam under leather or velour sounds like audiophile snake oil.
As a fan of vintage electrostatic headphones, I’ve confidently operated under this belief by chintzing out and buying replacement earpads of roughly the right size and shape rather than ponying up $100 or more for OEM. It never occurred to me that this might have been a mistake until I tested SJY’s new Zeph open-backed planar magnetic headphones.
The end result is far from a gimmick—they’re among my favorite pair of headphones of all the ones I’ve ever used.
Most consumer headphones and speakers reproduce sound by vibrating a cone using a wire coil. But the Zeph is different. It’s a planar magnetic headphone, which means it uses a magnetic field to vibrate a flat, thin diaphragm to reproduce sound. These have a faster and more accurate sound but are generally thought to sacrifice some punch on lower bass frequencies. Planar magnetics are a growing category that is expected to more than double in the next decade—even if these headphones remain niche today.
I’ve owned a few pairs of planar magnetics and am generally a fan because I like loads of detail in my music. True to form, the Zeph has exceptional detail and frequently delivers the hyper-real quality I look for in headphones of this range. It aced my favorite reference test, which is being able to hear Keith Moon move around on a squeaky stool during the opening of “Won't Get Fooled Again.” On Radiohead’s “Daydreaming” from A Moon Shaped Pool, the glockenspiel pierces through the piano and loops with a shimmery quality. Listen closely, and you can hear the metronome in the left channel (and that’s all with the less-detailed holes-in-front orientation). The precision and texture here is unprecedented. Meanwhile, there is plenty of low-end for my taste—I get a thick, bouncy bass when clicking forward to “Identikit.”
Note, though, that planar magnetic headphones generally require more amplification than standard headphones, and the Zeph is relatively power-hungry. It will demand at least a watt per channel, or preferably more. I have a handful of headphone amps and DAC dongles lying around, but only one device that can drive the Zephs. That’s a Creative Soundblaster X5 that has a balanced 4.4-mm headphone port. The 4.4-mm port is pretty standard on audiophile equipment these days, but it’s worth a warning to regular folks who are accustomed to standard 3.5-mm and 6.3-mm headphone jacks. You won’t be able to buy these headphones and plug them into even a standard stereo receiver.
The Zeph’s magnetic earpads are flippable, with one side having pinprick-thick microperforations and the other being smooth. You can tweak the sonic signature by swapping the seam from down to up. If the size with holes is in front of your ear, the tuning becomes slightly colder and wider, with added pop to instruments. Flip the pads over so that the millimeter-thick holes are behind your ear and the sound signature is a tad warmer and more cohesive, with mixes sounding more blended.
The disparity is relatively subtle—like the difference between a martini that’s stirred (holes in front) as opposed to shaken (holes in the back)—but it’s definitely audible. I tend to prefer headphones with an expansive soundstage and lots of detail. Though with the SJY, I find the slightly warmer and more natural sound more inviting for long listening sessions. And these are headphones that can live comfortably on your head for long stretches.
The impact of the simple switch of earpad orientation is made possible partly because of the design’s arch minimalism. The design was intended to have as few pieces as possible and to hold them rigidly in place with the goal of achieving purity of sound. The aluminum chassis, diaphragm, and driver all measure low, single-digit millimeters. T